HR: 16:00h
AN: H32G-01    [PDF]
TI: Montana's Coalbed Methane Ground-Water Monitoring Program: Year One
AU: * Wheaton, J R
EM: jwheaton@mtech.edu
AF: Montana Bureau of Mines and Geology, 1300 N. 27th Street, Billings, MT 59101 United States
AU: Smith, M
EM: msmith@mtech.edu
AF: Montana Bureau of Mines and Geology, 1300 N. 27th Street, Billings, MT 59101 United States
AU: Donato, T A
EM: tdonato@mtech.edu
AF: Montana Bureau of Mines and Geology, 1300 N. 27th Street, Billings, MT 59101 United States
AU: Bobst, A L
EM: andrew_bobst@blm.gov
AF: U. S. Bureau of Land Management, 111 Garryowen Road, Miles City, MT 59301 United States
AB: Tertiary coal seams in the Powder River Basin in southeastern Montana provide three very important resources: ground water, coal, and natural gas. Ground water from springs and wells is essential for the local agricultural economy. Because coal seams in the Fort Union Formation have higher hydraulic conductivity values and are more continuous than the sandstone units, they are the primary aquifers in this region. Coalbed methane (CBM) production is beginning in the Powder River Basin, and requires removal and management of large quantities of water from the coal-seam aquifers. The extensive pumping required to produce the methane is expected to create broad areas of severe potentiometric decline. The Montana CBM ground-water monitoring program, now in place, is based on scientific concepts developed during more than 30 years of coal-mine hydrogeology research. The program includes inventories of ground-water resources and regular monitoring at dedicated wells and selected springs. The program is now providing baseline potentiometric and water-quality data, and will continue to be active through the duration of CBM production and post-production ground-water recovery. An extensive inventory of ground-water resources in the Montana portion of the Powder River Basin has located 300 springs and 21 wells on private land, and 460 springs and 21 wells on U. S. Forest Service and U. S. Bureau of Land Management land, all producing ground water from the methane bearing strata. In southeastern Montana, 134 monitoring wells are currently included in the CBM monitoring program. They are completed either in coal seams, adjacent sandstone units, or alluvium. During the coal boom of the 1970's and 1980's many monitoring wells were drilled, but most have been since unused. Thirty-six of these existing wells have now been returned to service to decrease start-up costs for the CBM program. This network of existing wells has been augmented at key sites with 26 new wells drilled specifically for the CBM program and 72 existing wells from the coal-mine hydrogeology program. Additionally, drilling of about 25 more wells is in the planning stage. About 20 springs are being monitored specific to CBM. At all sites both water-quantity data (regular water levels, one-time aquifer testing, flow rates at springs) and water-quality data (field parameters or laboratory samples for major and minor constituents) are being collected. Monitoring locations and specific monitoring activities will continue to be adjusted in response to CBM development and data needs. All data collected as part of this program are made immediately available to the public on the Internet through the Montana Ground-Water Information Center (http://mbmggwic.mtech.edu/). Interpretive reports based on data collected will be published under standard scientific protocols. Data and reports will be used by industry, landowners, regulators and researchers in assessing impacts, lack of impacts and recovery of ground-water systems in relation to production of coalbed methane. Funding for this program has been provided by the U. S. Bureau of Land Management, U. S. Forest Service, U. S. Environmental Protection Agency, local Conservation Districts and the State of Montana. Coalbed methane production and consequent impacts to ground-water in this semi-arid region are controversial. Acceptance by all parties of data and interpretations resulting from the CBM monitoring program is enhanced by the credibility established through the more than 30-year history of the coal-mine hydrogeology program.
DE: 1803 Anthropogenic effects
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1884 Water supply
SC: Hydrology [H]
MN: 2003 Fall Meeting